Dimova, Maya, Gerard Panczer, and Michael Gaft. 2006. “Spectroscopic Study of Barite from the Kremikovtsi Deposit (Bulgaria) With Implication for Its Origin”. Geološki Anali Balkanskoga Poluostrva 67 (1), 101-8. https://doi.org/10.2298/GABP0667101D.